docs: def callback(self, callback):
          """
          Set callback for callback queries
  
          :Example:
  
          >>> @bot.callback
          >>> def echo(chat, cq):
          >>>     return cq.answer()
  
          >>> @bot.callback(r"buttonclick-(.+)")
          >>> def echo(chat, cq, match):
          >>>     return chat.reply(match.group(1))
          """
          if callable(callback):
              self._default_callback = callback
              return callback
          elif isinstance(callback, str):
  
              def decorator(fn):
                  self.add_callback(callback, fn)
                  return fn
  
              return decorator
          else:
              raise TypeError("str expected {} given".format(type(callback)))